1. Technical Field
The present invention relates to a printing technology for printing using a plurality of inks, and more particularly to printing using a light-blocking ink, a specialty gloss ink, and a color ink.
2. Related Art
In recent years, printing technologies for printing devices have appeared to become more diverse than mere color printing, especially in regard to printers for printing image data processed by a computer. Examples include a techniques whereby a white ink is applied to a printing medium in advance in order to reproduce an image, regardless of the ground color and texture of the medium to be printed, and color printing is performed thereon (Japanese Laid-Open Patent Publication No. 2007-282205); a technique whereby a light-blocking layer is formed for printing onto a light-transmissive printing medium (Japanese Laid-Open Patent Publication No. 2001-1560); and a technique whereby printing is performed to realize a special luster such as a metallic finish (Japanese Laid-Open Patent Publication No. 2006-50347).
However, research into printing technologies combining a plurality of inks other than color inks has been insufficient. For example, not enough research has been conducted into the differences in printing techniques for printing media having light-transmissive properties and printing media having light-diffusing properties. When the printing medium having light-transmissive properties is a transparent sheet, there are situations in which printing is performed so that the color printing can be viewed from the transparent sheet side. In these situations, the use of a large amount of metallic ink is being considered to block light from the rear. However, the metallic pigments used in metallic inks are typically expensive, and the use of metallic inks beyond a given quantity does not further improve the luster and lowers the brightness of color printing.